Purpose To evaluate the efficacy and safety of intravitreal ranibizumab (Lucentis) in patients with treatment-naive retinal vein occlusion.

Design Prospective, consecutive, non-comparative, interventional case series.

Participants Seventeen eyes of 17 consecutive patients with naive retinal vein occlusion.

Methods Consecutive patients were recruited and received, on demand, intravitreal 0.5 mg of ranibizumab; nine had central retinal vein occlusion (CRVO) and eight had branch retinal vein occlusion (BRVO). Pre- and postoperative clinical evaluation included measurement of best corrected visual acuity (BCVA) for distance, and near vision (MNREAD time, reading fluency), contrast sensitivity, colour fundus photography, fluorescein angiography and optical coherence tomography (OCT). All subjects were followed for a minimum of 12 months.

Main outcome measures Change in BCVA, contrast sensitivity, angiographic leakage, OCT central macular thickness (CMT), number of treatments.

Results Patients with CRVO had mean pre-treatment BCVA of 20/240 (1.08±0.25 logarithm of the minimum angle of resolution (logMAR)) and final BCVA of 20/46 (0.36±0.16 logMAR), with significant improvement at 1 year of follow-up (p<0.0001). At 12 months mean BCVA improved to 36.7 letters, with a gain of 6.4 lines, and OCT showed that the mean CMT was 271 μm, with a mean reduction of 360 μm (p<0.0001) from baseline (mean 631 μm). Patients with BRVO had mean pre-treatment BCVA of 20/126 (0.80±0.29 logMAR) and final BCVA of 20/50 (0.41±0.23 logMAR) (p<0.0001). The mean OCT CMT was 278 μm, with a mean reduction of 275 μm (p<0.0001) from baseline (mean 553 μm). Contrast sensitivity, MNREAD time and reading fluency improved significantly in the treated eyes. No ocular or systemic side effects were observed. Eyes with CRVO received an average of 3.0 injections (range 2–4) and those with BRVO 3.6 (range 3–4).

Conclusions Intravitreal ranibizumab for the management of naive CRVO or BRVO can favourably modify the course of the occlusion, indicating that short- and long-term blockade of vascular endothelial growth factor (VEGF)-A may restore the integrity of the inner blood–retinal barrier, reduce CMT and significantly improve visual function, with a good safety profile. Further prospective long-term studies are warranted to confirm the efficacy, safety and optimal treatment regimen for intravitreal ranibizumab.